The present invention relates to a system and method for detecting the severity of a crash of a vehicle.
Vehicles employ passenger safety systems such as air bags and passenger restraints that deploy when a vehicle crash is detected by a crash detection system. Typically, a crash detection system consists of an evaluation unit placed inside the vehicle. The evaluation unit has an electronic acceleration sensor, which detects changes in vehicle velocity from within the unit. The signal from this sensor is filtered and then amplified before processing by a controller. The controller then determines when to activate the vehicle""s air bag and passenger restraint systems. When a significant change is detected, the evaluation unit instructs the passenger safety system to deploy.
Currently, the electronic acceleration sensor is located with the evaluation unit in the console of the vehicle between the driver and passenger. However, this evaluation unit detects changes in the velocity of the vehicle only from a single location of the vehicle body. In a high-speed collision in contrast to a low-speed collision, the vehicle body will deform. Accordingly, the velocity of the vehicle body will vary across the area of the deformation. Current crash detection systems do not detect this difference in velocity and consequently do not measure the rate of vehicle body deformation, which indicates the degree of severity of a vehicle crash.
Air bag and restraint systems have been developed that deploy to varying degrees to accommodate the varying degrees of intensity of vehicle accidents. For example, air bags that inflate to a higher level in a high-speed collision than in a low-speed collision are known. Passenger restraints may also adjust the level of restraining force based on the accident""s intensity. A need therefore exists to determine more precisely the intensity of a vehicle collision.
In a disclosed embodiment of this invention, a plurality of electronic acceleration sensors is distributed at different locations of a vehicle body. The plural electronic acceleration sensors measure the change in acceleration of the vehicle body across the area of distribution. Signals from the plurality of electronic acceleration sensors are filtered, amplified, and passed to an evaluation unit, which reads and compares the signals. Based on the rate of deformation of the vehicle body, the evaluation unit then makes a determination of the severity of the vehicle crash and communicates this information to a passenger safety system.
The present invention accordingly measures the severity of a vehicle crash, communicating precise information about the accident to the passenger safety system. Moreover, the use of multiple electronic acceleration sensors creates crash detection system redundancy in event of electronic acceleration sensor failure.